Should middle and high schools start after 8:30 a.m.?

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As adolescents go through puberty, the timing of melatonin release — the hormone that promotes sleep — tends to shift later. As a result, teenagers often find themselves falling asleep and waking up later.

However, when schools start early in the morning, adolescents are often required to wake up earlier than their natural body clocks would prefer. This is one reason why many teenagers sleep late on weekends.

A recent study published in the international journal Sleep Medicine Reviews found that this difference in sleep schedules between weekdays and weekends, known as “social jetlag,” is associated with anxiety among adolescents.

Researchers from the University of Southampton’s department of psychology systematically reviewed studies examining the relationship between social jetlag and anxiety in adolescents aged 12 to 18. A total of 18 studies were included in the review, while data from 12 of those studies involving 235,526 adolescents was included in a meta-analysis.

The researchers found that adolescents with greater differences between their weekday and weekend sleep schedules tended to report higher levels of anxiety. Although the association between the two factors was small, it was statistically significant.

The researchers cautioned, however, that the study identified an association rather than proving that social jetlag directly causes anxiety.

“Nevertheless, these findings highlight the importance of maintaining consistent sleep and wake times throughout the week, including on weekends,” the researchers said. They also noted that school start times should be reconsidered in light of the biological changes in sleep patterns that occur during adolescence.

In the United States, major medical organizations have long recommended that middle and high schools start no earlier than 8:30 a.m. The American Academy of Pediatrics and the American Academy of Sleep Medicine (AASM) both recommend that classes for middle and high school students begin at or after 8:30 a.m. The AASM recommends that teenagers aged 13 to 18 get eight to 10 hours of sleep per day.

During puberty, adolescents undergo biological changes that shift their circadian rhythms later, making them naturally inclined to feel sleepy later at night and wake up later in the morning. Experts therefore say that simply telling teenagers to go to bed earlier may not be enough to ensure they get sufficient sleep.

Adequate sleep is also essential for the developing adolescent brain. During adolescence, brain functions involved in learning and memory, emotional regulation and decision-making continue to develop.

Deep sleep, in particular, plays an important role in consolidating and retaining information acquired during the day. In contrast, insufficient sleep can negatively affect not only concentration, learning and memory, but also emotional regulation, impulse control and judgment.

This article from Kormedi.com, Korea’s top health care and medical portal, is translated by a generative AI system and edited by The Korea Times.